Animal welfare chiefs are appealing for help after these two cats suffered “horrendous deaths” following a suspected poisoning.

Brother and sister Dexter and Millie were just a year old when they took ill suddenly and vets were unable to save them.

The children of the Carluke family they belonged to are devastated. Now the Scottish SPCA is trying to discover whether they were poisoned deliberately.

Drummond Pringle of Old Lanark Road let the cats out as normal on the morning of Friday, June 7, but they failed to return until Saturday evening when Millie appeared through the cat flap staggering and in distress.

The Pringle family took Millie to an emergency vet for treatment, however, her condition deteriorated and she fell into a coma and began fitting before she died.

Hours later, brother Dexter developed the same symptoms. Again, the Pringles rushed him to their local vet for treatment. However, he was suffering kidney failure and there was no option but to put him to sleep.

Mr Pringle said: “It was hard enough losing Millie but to lose Dexter straight afterwards and for both of them to have suffered in such a horrific way is just appalling.

“My kids are very upset and my daughter in particular is devastated as they were really her cats.

“I’m aware of at least eight other cats who have died in similar circumstances in this area in the past year so it’s very worrying.”

Scottish SPCA Chief Superintendent Mike Flynn said: “We do not know the exact cause of the poisoning in this particular incident, and we also cannot comment on whether this was a deliberate act or an unfortunate accident.

“However, it is clear that there is a source of poison somewhere in the local community.

“We are very keen to speak to anyone who knows anything about this matter.